Sugar inhibits the uptake of Vitamin C

At the first hint of a cold coming on a quick reaction might be to buy a carton of OJ and down it. Or to get an "immunity boosting" smoothie. Why? Vitamin C, of course. We all know that vitamin C is essential for proper immune function. But did you know that vitamin C is derived from glucose in most non-human animals, so sugar and vitamin C are very similar in structure?

Why is this important?

Due to their similarity in structure, vitamin C and glucose use the same pathway to pass into cells (assisted by insulin), and if they're both present in the bloodstream at the same time they compete to get in the door. And guess who gets preferential treatment? Sugar, of course. I mean, if there's a cookie and a high vitamin C red bell pepper in front of your face, which do you want more? But seriously, sugar at least means momentary sustenance to keep a cell alive, so sugar gets preferential treatment.

Where does this leave vitamin C? I'm assuming floating around, looking for a home, and if it can't find one it will eventually be excreted by the body.

What does Vitamin C do?

In the human body vitamin C:

  • acts as an antioxidant
  • acts as an electron donor for important enzymes
  • aids in the synthesis of collagen
  • aids in the synthesis of carnitine
  • assists in neutrophilic phagocytocis (white blood cells killing invaders)

A study in Mexico connected obesity to vitamin C deficiency. It's thought that due to chronically elevated insulin, sugar always has the leg up on vitamin C, even if it's consumed in adequate amounts, thus cells are constantly starved of this important nutrient.

What are some Low Carbohydrate sources of Vitamin C?

In order to give your cells the ability to uptake vitamin C, it might be best to ensure that insulin levels aren't spiked, and there isn't too much sugar competing to enter cells. This is where low carbohydrate foods high in vitamin C come in. These include low sugar fruits and veggies.

  • Bell Peppers
  • Broccoli
  • Brussels Sprouts
  • Cauliflower
  • Kale
  • Strawberries (in moderation)

Some higher sugar fruits are also great sources of vitamin C. Just consider eating them with a bit more moderation than you would vegetables that contain vitamin C. And always eat the whole fruit, not the juice version. The whole fruit contains fibers that slow digestion.

  • Oranges
  • Mango
  • Papaya
  • Kiwi

The Takeaway

Consuming high amounts of sugar (carbohydrate) with Vitamin C will inhibit your cell's ability to uptake this vital vitamin. Instead of drinking a glass of orange juice to get your Vitamin C, make a salad with baby kale or power greens, bell pepper, lean protein, orange slices, feta cheese, walnuts, and top it with some heart healthy olive oil (no need to skimp) to provide extra satiety.